===================================================================
RCS file: /home/cvs/OpenXM_contrib/gmp/mpz/Attic/scan0.c,v
retrieving revision 1.1.1.2
retrieving revision 1.1.1.3
diff -u -p -r1.1.1.2 -r1.1.1.3
--- OpenXM_contrib/gmp/mpz/Attic/scan0.c	2000/09/09 14:12:56	1.1.1.2
+++ OpenXM_contrib/gmp/mpz/Attic/scan0.c	2003/08/25 16:06:33	1.1.1.3
@@ -1,6 +1,6 @@
-/* mpz_scan0(op, startbit) -- Scan for the next set bit, starting at startbit.
+/* mpz_scan0 -- search for a 0 bit.
 
-Copyright (C) 1996 Free Software Foundation, Inc.
+Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
 
 This file is part of the GNU MP Library.
 
@@ -21,15 +21,104 @@ MA 02111-1307, USA. */
 
 #include "gmp.h"
 #include "gmp-impl.h"
+#include "longlong.h"
 
-unsigned long int
-#if __STDC__
-mpz_scan0 (mpz_srcptr u, unsigned long int starting_bit)
-#else
-mpz_scan0 (u, starting_bit)
-     mpz_srcptr u;
-     unsigned long int starting_bit;
-#endif
+
+/* mpn_scan0 can't be used for the u>0 search since there might not be a 0
+   bit before the end of the data.  mpn_scan1 could be used for the inverted
+   search under u<0, but usually the search won't go very far so it seems
+   reasonable to inline that code.  */
+
+unsigned long
+mpz_scan0 (mpz_srcptr u, unsigned long starting_bit)
 {
-  return mpn_scan0 (u->_mp_d, starting_bit);
+  mp_srcptr      u_ptr = PTR(u);
+  mp_size_t      size = SIZ(u);
+  mp_size_t      abs_size = ABS(size);
+  mp_srcptr      u_end = u_ptr + abs_size;
+  unsigned long  starting_limb = starting_bit / GMP_NUMB_BITS;
+  mp_srcptr      p = u_ptr + starting_limb;
+  mp_limb_t      limb;
+  int            cnt;
+
+  /* When past end, there's an immediate 0 bit for u>=0, or no 0 bits for
+     u<0.  Notice this test picks up all cases of u==0 too. */
+  if (starting_limb >= abs_size)
+    return (size >= 0 ? starting_bit : ULONG_MAX);
+
+  limb = *p;
+
+  if (size >= 0)
+    {
+      /* Mask to 1 all bits before starting_bit, thus ignoring them. */
+      limb |= (CNST_LIMB(1) << (starting_bit % GMP_NUMB_BITS)) - 1;
+
+      /* Search for a limb which isn't all ones.  If the end is reached then
+         the zero bit immediately past the end is returned.  */
+      while (limb == GMP_NUMB_MAX)
+        {
+          p++;
+          if (p == u_end)
+            return (unsigned long) abs_size * GMP_NUMB_BITS;
+          limb = *p;
+        }
+
+      /* Now seek low 1 bit. */
+      limb = ~limb;
+    }
+  else
+    {
+      mp_srcptr  q;
+
+      /* If there's a non-zero limb before ours then we're in the ones
+         complement region.  Search from *(p-1) downwards since that might
+         give better cache locality, and since a non-zero in the middle of a
+         number is perhaps a touch more likely than at the end.  */
+      q = p;
+      while (q != u_ptr)
+        {
+          q--;
+          if (*q != 0)
+            goto inverted;
+        }
+
+      /* Adjust so ~limb implied by searching for 1 bit below becomes -limb.
+         If limb==0 here then this isn't the beginning of twos complement
+         inversion, but that doesn't matter because limb==0 is a zero bit
+         immediately (-1 is all ones for below).  */
+      limb--;
+
+    inverted:
+      /* Now seeking a 1 bit. */
+
+      /* Mask to 0 all bits before starting_bit, thus ignoring them. */
+      limb &= (MP_LIMB_T_MAX << (starting_bit % GMP_NUMB_BITS));
+
+      if (limb == 0)
+        {
+          /* If the high limb is zero after masking, then no 1 bits past
+             starting_bit.  */
+          p++;
+          if (p == u_end)
+            return ULONG_MAX;
+
+          /* Search further for a non-zero limb.  The high limb is non-zero,
+             if nothing else.  */
+          for (;;)
+            {
+              limb = *p;
+              if (limb != 0)
+                break;
+              p++;
+              ASSERT (p < u_end);
+            }
+        }
+    }
+
+  /* Mask to 0 all bits above the lowest 1 bit. */
+  ASSERT (limb != 0);
+  limb &= -limb;
+
+  count_leading_zeros (cnt, limb);
+  return (p - u_ptr) * GMP_NUMB_BITS + GMP_LIMB_BITS - 1 - cnt;
 }